1. Field of the Invention
The present invention relates to a method for producing a dispersible xanthan gum product. More specifically, the method comprises the addition of glyoxal to xanthan gum under alkaline conditions, followed by treating the resulting product with acid to form the hemiacetal linkages between the xanthan gum and glyoxal. The resulting product more uniformly distributes the glyoxal across the xanthan gum particles. In addition, the product can be designed with a specifically controlled hydration rate profile and has improved age stability.
2. Technology Description
Xanthan gum is an excellent and widely used suspending and viscosity building agent. Some of its particular uses are in oil well fluids, paints, sprays and cleaning fluids. Xanthan gum however has few disadvantages. It is very difficult to disperse and wet in water or brine so that hydration can take place. A high degree of shear is usually necessary to wet each gum particle. Once dispersal and wetting are accomplished the hydration of the gum, as evidenced by the development of viscosity, is quite rapid.
U.S. Pat. No. 4,041,234 discloses dispersible glyoxal-xanthan gum complexes. According to the patent, in a preferred mode, glyoxal is added to a xanthan gum fermentation broth for the purpose of improving the dispersibility of the xanthan gum. Alternative methods proposed comprise mulling xanthan gum and glyoxal in a mortar with enough water to effect reaction or to spray an aqueous solution of glyoxal onto tumbling xanthan gum particles followed by drying the resulting material. The reference further discloses that the reaction between the xanthan gum and glyoxal can take place at a pH of up to 8. The reference does not teach nor suggest that the xanthan gum be treated with a base prior to the glyoxal addition, holding the mixture under basic conditions for a time period sufficient to enable the glyoxal to homogeneously permeate the xanthan gum particles and adding acid after the glyoxal has permeated the xanthan gum particles. As a result, high amounts of glyoxal are required to adequately disperse the resulting material when added to an aqueous solution.